How to change IP address to domain

I had someone set up CWP on my VPS and he used my IP address instead of my domain name during the setup so in order to access the admin or user panels, I have to remember the the IP address to type it in the browser.

Hw can I change this so that I can use my domain name for example https://cwp.mydomain:2083  ?

Just create an account on your VPS with the domain name you want to use, point the domain name to your VPS and then you will be able to access CWP over the URLs like:
https://yourdomain.com:2083/
https://yourdomain.com:2087/